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8366968: Exhaustive switch expression rejected by for not covering all possible values #27547

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8366968: Exhaustive switch expression rejected by for not covering all possible values #27547

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8366968: Exhaustive switch expression rejected by for not covering al…
lahodaj Sep 26, 2025
bcc8305
There are no relevant permitted subtypes of a non-abstract class, not…
lahodaj Oct 2, 2025
64df6f4
Removing trailing whitespace.
lahodaj Oct 2, 2025
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21 changes: 15 additions & 6 deletions src/jdk.compiler/share/classes/com/sun/tools/javac/comp/ExhaustivenessComputer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -213,7 +213,6 @@ private Set<PatternDescription> reduceBindingPatterns(Type selectorType, Set<Pat
if (clazz.isSealed() && clazz.isAbstract() &&
//if a binding pattern for clazz already exists, no need to analyze it again:
!existingBindings.contains(clazz)) {
ListBuffer<PatternDescription> bindings = new ListBuffer<>();
//do not reduce to types unrelated to the selector type:
Type clazzErasure = types.erasure(clazz.type);
if (components(selectorType).stream()
Expand All @@ -232,16 +231,26 @@ private Set<PatternDescription> reduceBindingPatterns(Type selectorType, Set<Pat

return instantiated != null && types.isCastable(selectorType, instantiated);
});
Set<Symbol> filteredPermitted = new HashSet<>(permitted);

for (PatternDescription pdOther : patterns) {
if (pdOther instanceof BindingPattern bpOther) {
Set<Symbol> currentPermittedSubTypes =
allPermittedSubTypes(bpOther.type.tsym, s -> true);
Set<Symbol> currentSubTypes;

if (bpOther.type.tsym.isAbstract()) {
currentSubTypes =
permitted.stream()
.filter(perm -> types.isSubtype(types.erasure(perm.type),
types.erasure(bpOther.type)))
.collect(Collectors.toSet());
} else {
currentSubTypes = Set.of();
}

PERMITTED: for (Iterator<Symbol> it = permitted.iterator(); it.hasNext();) {
PERMITTED: for (Iterator<Symbol> it = filteredPermitted.iterator(); it.hasNext();) {
Symbol perm = it.next();

for (Symbol currentPermitted : currentPermittedSubTypes) {
for (Symbol currentPermitted : currentSubTypes) {
if (types.isSubtype(types.erasure(currentPermitted.type),
types.erasure(perm.type))) {
it.remove();
Expand All @@ -256,7 +265,7 @@ private Set<PatternDescription> reduceBindingPatterns(Type selectorType, Set<Pat
}
}

if (permitted.isEmpty()) {
if (filteredPermitted.isEmpty()) {
toAdd.add(new BindingPattern(clazz.type));
}
}
Expand Down
53 changes: 52 additions & 1 deletion test/langtools/tools/javac/patterns/Exhaustiveness.java
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@

/**
* @test
* @bug 8262891 8268871 8274363 8281100 8294670 8311038 8311815 8325215 8333169 8327368 8364991
* @bug 8262891 8268871 8274363 8281100 8294670 8311038 8311815 8325215 8333169 8327368 8364991 8366968
* @summary Check exhaustiveness of switches over sealed types.
* @library /tools/lib
* @modules jdk.compiler/com.sun.tools.javac.api
Expand Down Expand Up @@ -2276,6 +2276,57 @@ record Root(R2 b2, R2 b3) {}
"1 error");
}

@Test //JDK-8366968
public void testNonSealedDiamond(Path base) throws Exception {
doTest(base,
new String[0],
"""
class Demo {

sealed interface Base permits Special, Value {}

non-sealed interface Value extends Base {}

sealed interface Special extends Base permits SpecialValue {}

non-sealed interface SpecialValue extends Value, Special {}

static int demo(final Base base) {
return switch (base) {
case Value value -> 0;
};

}

}
""");
}

@Test //JDK-8366968
public void testNonAbstract(Path base) throws Exception {
doTest(base,
new String[0],
"""
class Demo {
sealed interface I permits Base, C3 { }
sealed class Base implements I permits C1, C2 { }
final class C1 extends Base { }
final class C2 extends Base { }
final class C3 implements I { }

void method1(I i) {
switch (i) {
case C1 _ -> {}
case C2 _ -> {}
case C3 _ -> {}
}
}
}
""",
"Demo.java:9:9: compiler.err.not.exhaustive.statement",
"1 error");
}

private void doTest(Path base, String[] libraryCode, String testCode, String... expectedErrors) throws IOException {
doTest(base, libraryCode, testCode, false, expectedErrors);
}
Expand Down